Method and device for detecting a water change in a water-bearing household appliance, in particular a dishwasher

ABSTRACT

The present invention relates to a method and device for dispensing a rinse aid preparation into the interior of a dishwasher comprising a sensor for detecting water, a sensor for detecting temperature, a control unit for processing the sensor data, wherein the control unit is configured to perform the method according to the invention.

FIELD OF THE INVENTION

The present invention generally relates to a method and a device for detecting a water change in a water-conveying domestic appliance, in particular a dishwasher.

BACKGROUND OF THE INVENTION

Automatic dispensing devices which operate autonomously of a dishwasher and release a plurality of differing preparations into the washing process with a time delay are known from the prior art.

Such dispensing devices operate comparatively reliably providing that they are operated within typical and static washing programs.

However, in the field of dishwashing machine programs, “automatic programs” have become established which can dynamically adapt or modify their program sequences on the basis of supplied sensor data, such as for example from a turbidity sensor, in order to be capable of providing a result which is optimized in terms of energy, water consumption or washing result in line with the machine load and level of soiling present, without requiring any user intervention to achieve this.

The start of a washing program, even of automatic programs, can be reliably detected using the above-mentioned dispensing devices, but these dispensing devices reach the limits of their capabilities when releasing preparations, in particular in the rinsing section of a washing program, since, due to the dynamic adaptation of washing programs in automatic programs, dispensing a rinsing phase once a defined time has elapsed from the detection of the start of the washing program may result in release before the start of the rinsing section in an automatic program. Since in such a case the rinse aid preparation is not present in the rinsing program, as a water change conventionally occurs before a rinsing section within a washing program, the resultant washing result is frequently not ideal.

Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.

BRIEF SUMMARY OF THE INVENTION

A method for detecting a water change in a water-conveying domestic appliance, in particular a dishwasher, comprising: a sensor for detecting water, a sensor for detecting temperature, and a control unit for processing the sensor data wherein the method comprises the following steps: (a.) detecting water in a defined time interval of 2-120 s, preferably 5-60 s, particularly preferably 10-30 s, wherein method step (b.) is performed after the absence of water has been detected at at least two, preferably at least three, consecutive measuring points within a time interval ZI_(w,1) (b.) detecting water in a defined time interval ZI_(w,2) of 1 ms-120 s, preferably 5 ms-60 s, particularly preferably 10 ms-30 s, wherein method step (c.) is performed after the presence of water has been established at least once within the time interval ZI_(w,2); (c.) detecting the temperature in a time interval ZI_(T,3) of 2-120 s, preferably 5-60 s, particularly preferably 10-30 s, wherein method step (d.) is performed if, at at least two, preferably at least three, consecutive temperature measuring intervals ZI_(T,4) within the time interval ZI_(T,3), the temperature T₁ at the start of the measuring interval ZI_(T,3) is greater than the temperature T₂ at the end of the measuring interval ZI_(T,3); (d.) performing method step (e.) if the time between the detection of water according to method step (b.) and at least three consecutive detections of a negative temperature gradient according to method step (c.) is less than two minutes; (e.) generating a control signal by the control unit on the basis of a detected water change according to method steps (a.) to (d.).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and

FIG. 1 is the dispensing device in a dishwasher; and

FIG. 2 is a flow diagram of water change recognition.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description of the invention is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description of the invention.

The method according to the invention for detecting a water change in a water-conveying domestic appliance, in particular a dishwasher, comprises a sensor for detecting water, a sensor for detecting temperature and a control unit for processing the sensor data wherein the method comprises the following steps:

-   -   (a.) detecting water in a defined time interval ZI_(w,1) of         2-120 s, preferably 5-60 s, particularly preferably 10-30 s,         wherein method step (b.) is performed after the absence of water         has been detected at at least two, preferably at least three,         consecutive measuring points within a time interval ZI_(w,1),     -   (b.) detecting water in a defined time interval ZI_(w,2) of 1         ms-120 s, preferably 5 ms-60 s, particularly preferably 10 ms-30         s, wherein method step (c.) is performed after the presence of         water has been established (at least) once within the time         interval ZI_(w,2),     -   (c.) detecting the temperature in a time interval ZI_(T,3) of 2         -120 s, preferably 5-60 s, particularly preferably 10-30 s,         wherein method step (d.) is performed if, at at least two,         preferably at least three, consecutive temperature measuring         intervals ZI_(T,4) within the time interval ZI_(T,3), the         temperature T₁ at the start of the measuring interval ZI_(T,3)         is greater than the temperature T₂ at the end of the measuring         interval ZI_(T,3),     -   (d.) performing method step (e.) if the time between the         detection of water according to method step (b.) and at least         three consecutive detections of a negative temperature gradient         according to method step (c.) is less than two minutes,     -   (e.) generating a control signal by the control unit on the         basis of a detected water change according to method steps (a.)         to (d.).

It is particularly preferred for the control signal after a detected water change to effect dispensing of a rinse aid preparation into the interior of a dishwasher. This in particular ensures that a rinse aid preparation is dispensed into the rinsing section at the end of an automatic program.

In one particularly preferred embodiment of the method according to the invention, the method comprising method steps (a.)-(e.) is only performed once at least one first dishwashing preparation, preferably an enzyme-containing dishwashing preparation, has been released into the interior of the dishwasher, wherein the at least first dishwashing preparation is released when at least a temperature of >25°, preferably of >29° C. and the presence of water have been detected. A detailed description of the detection of the beginning of a washing program was disclosed by the applicant in DE10 2010 002 750.2, wherein DE 10 2010 002 750.2 is included by reference in the disclosure content of the present application. It is thus particularly advantageous only to perform the method according to the invention once at least one cleaning agent preparation has already been released at the start of the washing process.

It is very particularly advantageous in this connection for the preparations which are dispensed into the washing process to differ from one another, wherein it is in particular advantageous for the preparations which are dispensed at the start of the washing process and the preparations which are added after detection of a water change to differ from one another.

In a further preferable development of the invention, the method comprising method steps (a.)-(e.) is performed, after the release of the first dishwashing preparation, once at least one second dishwashing preparation, preferably an alkaline dishwashing preparation, has been released into the interior of the dishwasher.

The present invention furthermore relates to a device for dispensing a rinse aid preparation into the interior of a dishwasher comprising a sensor for detecting water, a sensor for detecting temperature, a control unit for processing the sensor data, wherein the control unit is configured to perform the method according to the invention.

The dispensing device is preferably freely positionable by a user in the interior of a dishwasher. It is furthermore advantageous for the device to comprise a cartridge having at least one chamber in which at least one rinse aid preparation is stored.

Dispensing Device

The dispensing device comprises a dispenser having a cartridge coupled detachably or nondetachably to the dispenser, which cartridge comprises at least one chamber with a dishwashing preparation. The control unit necessary for performing the method according to the invention together with at least one sensor for detecting water and a sensor for detecting temperature are in particular integrated in the dispenser. An actuator for releasing a dishwashing preparation and/or an energy source are preferably likewise arranged on or in the dispenser.

Sensors

The dispensing device preferably comprises at least one sensor for detecting water and a sensor for detecting temperature. The temperature sensor is designed in particular to detect a water temperature.

It is additionally preferred for the dispensing device to comprise a sensor for detecting conductivity, whereby in particular the presence of water or the spraying of water, in particular in a dishwasher, is detected.

In one advantageous development of the invention, the sensor unit comprises at least one at least bipolar conductivity sensor. Preferably, at least two poles of the conductivity sensor are spaced apart by 2-25 mm, preferably 5-15 mm, particularly preferably approx. 12 mm.

It has proved particularly advantageous for at least two poles of a conductivity sensor to be enveloped with an electrically conductive silicone, wherein it is particularly preferable for a substantially planar area to be formed between the silicone and an external surface of the dispenser. Due to the elastomeric properties of the conductive silicone, the sensor can be simply and effectively sealed relative to the surrounding environment and be set in a housing wall of the dispenser.

In order to ensure ongoing measurement accuracy across a plurality of measurements, it is advantageous for the polarity of the bipolar conductivity sensor to be reversed after each resistance measurement, such that no charge excesses can form on the conductivity sensor.

It is particularly preferable for at least two sensor units to be provided for measuring different parameters, wherein very particularly preferably one sensor unit is a conductivity sensor and a further sensor unit is a temperature sensor.

The sensors are in particular adjusted for detecting the start, progress and end of a washing program. By way of non-exhaustive examples, the sensor combinations listed in the following table may be used for this purpose.

Sensor 1 Sensor 2 Sensor 3 Sensor 4 Conductivity Temperature sensor sensor Conductivity Temperature Brightness sensor sensor sensor Conductivity Temperature Brightness Turbidity sensor sensor sensor sensor

Using the conductivity sensor, it is possible, for example, to detect whether the conductivity sensor has been wetted with water, such that it may for example thereby be established whether there is water in the dishwasher.

The conductance/conductivity sensor may consist of an electrically conductive anode and a cathode which project out from the housing of the dispenser into the interior the dishwasher or are electrically conductively connected to the interior of the dishwasher. The spacing between the anode and cathode is preferably selected such that, when the dishwasher is in operation, an electrically conductive water bridge can form between the anode and cathode, this being measurable by a drop in resistance between anode and cathode.

Washing programs as a rule exhibit a characteristic temperature profile, which is determined inter alia by the heating of the washing water and drying of the items being washed, and which may be detected using a temperature sensor.

To allow efficient production and assembly of the dispenser, it is also possible, however, for at least one sensor unit to be arranged on or in the control unit. For example, it is possible to provide a temperature sensor in the dispenser or directly on the board bearing the control unit, such that the temperature sensor does not have any direct contact with the surrounding environment.

Control unit

A control unit for the purposes of the present application is a device which is suitable for influencing the transport of material, energy and/or information. To this end, the control unit acts by control signals on actuators with the assistance of information, in particular sensor unit measurement signals, which it processes for the purposes of the control objective.

The control unit may in particular comprise a programmable microprocessor. In one particularly preferred embodiment of the invention, a plurality of dispensing programs are stored in the microprocessor.

In a preferred embodiment, the control unit is not connected to any controller which may be present in the domestic appliance. Accordingly, no information, in particular electrical, optical or electromagnetic signals, is exchanged directly between the control unit and the controller of the domestic appliance.

In an alternative development of the invention, the control unit is coupled to the existing controller of the domestic appliance. This coupling is preferably effected wirelessly. It is possible, for example, to position a transmitter on or in a dishwasher, preferably on or at the dispensing chamber set into the door of the dishwasher, which transmits a signal wirelessly to the dispensing device if the controller of the domestic appliance brings about dispensing for example of a cleaning agent from the dispensing chamber or of rinse aid. It is thus possible for the dishwasher controller to transmit control signals to the dispensing device for releasing specific preparations and quantities to be dispensed.

Should the coupling between the dishwasher controller and the dispensing device controller be disrupted, for example should there be a breakdown in wireless signal transmission, it is also conceivable for such a signal breakdown to be detected by the dispensing device controller and for operation to be changed back to an internal dispensing program, such that, despite the disruption to signal transmission, it is ensured that preparation continues to be dispensed from the dispensing device into the washing process. A corresponding method was described by the applicant in DE 10 2009 009 194.7, wherein said application is included by reference in the disclosure content of the present application.

Release of preparations from the dispenser may proceed in sequence or simultaneously.

It is particularly preferable to dispense a plurality of preparations in sequence in a washing program. The following dispensing sequences are particularly preferable

1st dispensing 2nd dispensing 3rd dispensing 4th dispensing Enzymatic Alkaline cleaning cleaning preparation preparation Alkaline Rinse aid cleaning preparation Enzymatic Alkaline Rinse aid cleaning cleaning preparation preparation Enzymatic Alkaline Rinse aid Disinfectant cleaning cleaning preparation preparation preparation Enzymatic Alkaline Rinse aid Scent cleaning cleaning preparation preparation Pretreatment Enzymatic Alkaline Rinse aid preparation cleaning cleaning preparation preparation

It is additionally advantageous for at least one enzyme-containing preparation and/or alkaline preparation to be released in the prewash and/or main wash program of the dishwasher, wherein the enzyme-containing preparation is preferably released before the alkaline preparation. It is furthermore preferred for the rinse aid to be dispensed in the rinsing program of the dishwasher, wherein the rinsing program is recognized by a water change according to the method according to the invention described herein.

According to a further preferred embodiment of the invention, a discontinuous, discrete resistance measurement is carried out at the conductivity sensor and preferably also at the temperature sensor. The discontinuous, discrete measurement in particular reduces the electrical energy consumption of the control unit.

The invention is explained in greater detail below with reference to the figures, in which:

FIG. 1 is the dispensing device in a dishwasher

FIG. 2 is a flow diagram of water change recognition

FIG. 1 shows a dispensing device consisting of a positionable dispenser 2 with a two-chamber cartridge 1 in the crockery drawer 11 of a dishwasher 38 with the dishwasher door 39 open. A control unit, a temperature sensor and a conductivity sensor are arranged in the dispenser 2. It will be noted that the dispenser 2 together with the cartridge 1 is in principle positionable at any desired point within the crockery drawer 11, wherein it is advantageous for a plate- or cup-shaped dispensing system 1, 2 to be provided in a corresponding plate or cup receptacle in the crockery drawer 11.

In the dishwashing machine door 39 there is located a dispensing chamber 53, into which a dishwashing machine cleaning preparation may be introduced, for example in the form of a tablet. An advantage of this embodiment of the invention is that, when the positionable dispensing system 1, 2 is arranged in the lower or upper (not shown) crockery drawer 11, preparations 40 a, 40 b are released from the cartridge 1 directly via the outlet orifices arranged on the dispenser into the washing liquor, such that quick dissolution and uniform distribution of the washing preparations in the washing program is ensured. This furthermore ensures that, in the indicated operational position of the dispenser, the conductivity sensor is arranged on the dispenser at the bottom in the direction of gravity, and when the dishwasher is in operation the conductivity sensor is directly sprayed with washing water by a washing arm and the control unit and conductivity sensor are configured such that a discontinuous, discrete resistance measurement is carried out at the conductivity sensor and preferably also at the temperature sensor.

FIG. 2 shows an exemplary embodiment of the method according to the invention in the form of a flow diagram, wherein the method comprises the following steps:

-   -   (a.) detecting water in a defined time interval ZI_(w,1) of         2-120 s, preferably 5-60 s, particularly preferably 10-30 s,         wherein method step (b.) is performed after the absence of water         has been detected at three consecutive measuring points within a         time interval ZI_(w,1),     -   (b.) detecting water in a defined time interval ZI_(w,2) of 1         ms-120 s, preferably 5 ms-60 s, particularly preferably 10 ms-30         s, wherein method step (c.) is performed after the presence of         water has been established once within the time interval         ZI_(w,2),     -   (c.) detecting the temperature in a time interval ZI_(T,3) of         2-120 s, preferably 5-60 s, particularly preferably 10-30 s,         wherein method step (d.) is performed if, at three consecutive         temperature measuring intervals ZI_(T,4) within the time         interval ZI_(T,3), the temperature T₁ at the start of the         measuring interval ZI_(T,3) is greater than the temperature T₂         at the end of the measuring interval ZI_(T,3). To this end, the         measured temperatures T₁ and T₂ are in each case written to an         internal memory of the control unit, as are likewise the         measured times t_(b) at the start of method step (c.) and t_(c)         at the end of method step (c.)     -   (d.) performing method step (e.) if the time between the         detection of water according to method step (b.) and at least         three consecutive detections of a negative temperature gradient         according to method step (c.) is less than two minutes, thus if         the condition t_(c)−t_(b)<2 min is met,     -   (e.) generating a control signal by the control unit on the         basis of a detected water change according to method steps (a.)         to (d.).

While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims and their legal equivalents. 

What is claimed is:
 1. A method for detecting a water change in a water-conveying domestic appliance, in particular a dishwasher, comprising: a sensor for detecting water; a sensor for detecting temperature; a control unit for processing the sensor data; wherein the method comprises the following steps: (a.) detecting water in a defined time interval ZI_(w,1) of 2-120 s, wherein method step (b.) is performed after the absence of water has been detected at at least two, consecutive measuring points within a time interval ZI_(w,1), (b.) detecting water in a defined time interval ZI_(w,2) of 1 ms-120 s, wherein method step (c.) is performed after the presence of water has been established at least once within the time interval ZI_(w,2), (c.) detecting the temperature in a time interval ZI_(T,3) of 2-120 s, preferably 5-60 s, wherein method step (d.) is performed if, at at least two, consecutive temperature measuring intervals ZI_(T,4) within the time interval ZI_(T,3), the temperature T₁ at the start of the measuring interval ZI_(T,3 is greater than the temperature T) ₂ at the end of the measuring interval ZI_(T,3), (d.) performing method step (e.) if the time between the detection of water according to method step (b.) and at least three consecutive detections of a negative temperature gradient according to method step (c.) is less than two minutes, (e.) generating a control signal by the control unit on the basis of a detected water change according to method steps (a.) to (d.).
 2. The method according to claim 1, wherein the control signal, after a detected water change, effects dispensing of a rinse aid preparation into the interior of a dishwasher.
 3. The method according to claim 1, wherein the method comprising method steps (a.)-(e.) is performed once at least one first dishwashing preparation has been released into the interior of the dishwasher, wherein the at least first dishwashing preparation is released when at least a temperature of >25° and the presence of water have been detected.
 4. The method according to claim 1, wherein the method, comprising method steps (a.)-(e.), is performed, after the release of the first dishwashing preparation, once at least one second dishwashing preparation, has been released into the interior of the dishwasher.
 5. A device for dispensing a rinse aid preparation into the interior of a dishwasher comprising: a sensor for detecting water; a sensor for detecting temperature; a control unit for processing the sensor data; wherein the control unit is configured to perform the method according to claim
 1. 6. The device according to claim 5, wherein the device is freely positionable by a user in the interior of a dishwasher.
 7. The device according to claim 5, wherein the device comprises a cartridge having at least one chamber in which at least one rinse aid preparation is stored.
 8. The device according to claim 7, wherein the cartridge comprises at least three chambers, in which an enzyme-containing preparation, an alkaline preparation and a rinse aid preparation are stored.
 9. The device according to claim 5, wherein the control unit is couplable, in particular wirelessly, with the existing controller of the domestic appliance. 